High-pressure hydraulic system



April 7, 1970 w. s. VARGO HIGH-PRESSURE HYDRAULIC SYSTEM Filed NOV. 13,1967 L LOAD I L I INVENTOR. WILLIAM S. VARGO ATTO RNEY 2 United StatesPatent 3,504,882 HIGH-PRESSURE HYDRAULIC SYSTEM William S. Vargo, BayCity, Mich., assignor to Eltra Corporation, Toledo, Ohio Filed Nov. 13,1967, Ser. No. 682,247 Int. Cl. F16k 25/00 US. Cl. 25l63.4 ClaimsABSTRACT OF THE DISCLOSURE A high-pressure hydraulic system with areversible pump to move a load in both directions by a double-actinghydraulic cylinder including a valving system which is mechanicallyactuable and pressure actuable to protect the system against excessivepressure, yet is capable of maintaining a load in a predeterminedposition for prolonged periods of time by stabilizing the pressureconditions.

It is a principal object of this invention to provide a high-pressurehydraulic system which is capable of controlling the movements of a loadin both directions by a reversible hydraulic pump which will maintainthe load in a predetermined position for prolonged periods of time bystabilizing the pressure conditions in the system.

It is a further object of this invention to provide movable valves for ahydraulic system which are provided with elastometer sealing membersarranged in confining chambers whereby high pressures of the order of4500 pounds per square inch can be held for prolonged periods of time sothat loads being moved by hydraulic jacks in the hydraulic system can bemaintained at predetermined operative positions.

Other objects and advantages of this invention relating to thearrangement, operation and function of the related elements of thestructure, to various details of construction to combinations of partsand to economics of manufacture will be apparent to those skilled in theart upon consideration of the following description and appended claims,reference being had to the accompanying drawings forming a part of thisspecification wherein like reference characters designate correspondingparts in the several views.

FIG. 1 is an elevational view in section showing a hydraulic system towhich the invention has been applied;

FIG. 2 is an elevational view in section of a check vlave to which theinvention has been applied;

FIG. 3 is an elevational view in section of another form of a valve towhich the invention has been applied;

FIG. 4 is an enlarged cross-sectional view of the portion of the valveshown in FIG. 3; and

FIG. 5 is an end elevational view of the movable valve element shown inFIG. 3.

Referring to FIG. 1 of the drawings, a reservoir is shown in the floor112 of which a gear pump .14 is mounted, driven by a reversible electricmotor 16 by a vertical drive shaft 118. The details of the gear pump orany equivalent pump will not be described in further details as they arewell known in the art. The pump must be such that it can develop arelatively hydraulic pressure of the order of 4500 pounds per squareinch by compressing a hydraulic fluid of a suitable type with which thereservoir 10 is filled for the purpose of supplying the operablehydraulic system to be described hereinafter.

When the electric motor 16 is driven in one direction such ascounterclockwise drive end head, pressure is built up in the hydraulicfluid in passageway 20 which closes normally open valve 21 and whichurges the per- 3,504,882 Patented Apr. 7, 1970 "ice forated spool 22 tothe left to place the fluid pressure through the perforations 22a on thevalve incorporating the invention mounted in core 24 to allow the fluidto flow into annular chamber 26 and out through tube 28 to the lowerside of the piston 30 movably mounted in cylinder 32. The spool 22 andthe core 24 are sealed by suitable O-rings R.

The annular chamber 26 is also in communication with a vertical bore 34by passageway 36 which places the pressure created by the pump on thelower side of a valve assembly 33 shown in FIG. 2 (shown by arrows)which is mounted in sealed relation in a vertical bore 34 in the housingmember. When the external load on the piston rod causes the pressureunder the piston to exceed a predetermined safe value in chamber 26,this relief valve is actuated to allow the hydraulic fluid to flow backinto the reservoir 10 as will be described in further detailhereinafter. In the same manner, when the pump pressure in chamber 20exceeds a predetermined safe value, a regulating valve 38 will open toallow the fluid to again flow back into the reservoir, so that the pumpwhich can produce pressures in excess of 3000 pounds per square inch canalso be used in systems which do not require this high pressure.

The hydraulic fluid trapped above the piston 30 in the cylinder 32 willflow back to the reservoir .10 via tube 40 into chamber 42 and back tothe gear pump, additional fluid to compensate for the volume of thepiston rod is drawn from the reservoir through normally open valve 43.When the gear pump 14 is stopped, the flow of hydraulic fluid ceases andthe load on the hydraulic cylinder stops at the desired predeterminedposition and will remain in this position unless there is leakage in thesystem on the lower side of the piston 30 either in the seals in thevarious parts or by leakage of the valve 33 or the valve positioned inthe core 24. The valves herein disclosed are designed to hold the loadin its predetermined position for prolonged periods of time. Someapplications require that the pressure drop in the system shall not bemore than 400 pounds per square inch in 30 minutes, and the valvedisclosed herein can easily meet these severe requirements.

When it is desired to move the load downward by the hydraulic cylinderand piston 30- the gear pump -14 is reversed in its rotation by themotor 16, which moves the hydraulic fluid from the chamber 20 into thechamber 42, which after closing normally open valve 43 will build uphydraulic pressure in the chamber 42 to be communicated to the upperside of the piston 32 in the cylinder 32 by tube 40, and move the pistondownwardly. At the same time, spool 22 will be moved to the right by thepressure in chamber 42 to open the valve in the core 24 by physicalcontact of the projection 22b (FIG. 3) with the movable valve members aswill be described further hereinafter, to allow the excess fluid fromthe lower side of the piston due to piston rod volume to flow back intochamber 20 and into the reservoir 10 via normally open valve 21. Thenormally open valves 21 and 43 allow the pump to compensate for thedifferent volumes of hydraulic fluid required for movement of the piston30, due to the diiference in volume arising from the piston roddisplacement. The chamber 42 is also protected from excessive pressuresby regulating valve 46 as is well known in the art.

The relief valve 33 shown in FIG. 2 which relieves eX- cessive pressurein chamber 26 as described hereinbefore, consists of a cylindrical baseelement 48, the outer surface of which is provided with an annulargroove 50 in which is seated a suitable O-ring 52 to seal the body inthe vertical bore 34 as already described. The base element is held inthe bore in any suitable manner as by member 54 which also serves otherfunctions which will be obvious to a man skilled in the art. The basemember 48 is counterbored from each side along its axis to provide acentral wall 56 which is pierced by an aperture 58 through which thefluid flows for pressure relief of the chamber 36. Extending to theaperture 58, a valve pintle 60 is provided which has a head 62, abovewhich an integral spring anchor 64 is positioned for a helical biasingspring 66, the other end of the spring being adjustably anchored on bolt68 in the member 54. The pintle 60 is dimensional to fit closely intothe aperture 58 with minimum clearance and extends a substantialdistance below the wall to 56 to cooperate with a toroidal sealingmember 70 of rubber or other elastomeric material having a Durometerhardness of 80. The opening of the aperture 58 adjacent the sealingmember 70 is made clean and sharp to prevent extrusion of theelastomeric material, while the opposite end of the aperture 58 isflared as shown.

The sealing ring member 70 is provided with an annular depression 70a onits lower face to provide an enlarged edge 70b on its outer perimeterwhich is slightly compressed by the retainer plate 72 which holds thesealing member in its counterbore 74, while it is seated in its owncounterbore 76 of slightly large diameter by an inturned lip 78 whichmay also hold a filter screen 80 in position to prevent ingress ofcontaminents into the valve body. The retainer plate 72 has a centralaperture 72b in alignment with the aperture 58 in the wall 56, with itslower face being dished as shown. The inner face thereof is providedwith a clearance 72a to allow the formation of a chamber 73 for fluid toenter to place pressure on the lower face of the sealing member 70including the walls of the annular depression 70a.

The central aperture 700 of the toroidal sealing member 70 is slightlysmaller in dimension than the outer diameter of the valve pintle 60 sothat a sealing tension is provided when the parts are in cooperatingrelation to form the seal. The upper edge of the central aperture 70c isrounded and given a blending radius to form a toroidal cross-sectionalportion at the point where cooperation is bad with the cylindrical outersurface of the pintle 60 while the lower edge terminates in a sharpcorner as shown. The lower end of the pintle 60 is a given hemisphericalconformation to aid in the relative movement of the parts in theircooperative relation to seal and unseal as the pressure conditions inthe chamber 26 require.

The fluid pressure in chamber 26 is in constant communication with thechamber 73 adjacent the sealing member 70 and applies pressure bothoutwardly against its enlarged rim 70b and inwardly against toroidalsection to press the elastomeric sealing member against the pintle 60.This provides an enduring seal in both directions and assures that noleaking will occur until the pressure on the end of the pintle 60 issuflicient to displace the compression spring 66 and allow movementupwardly of the pintle to open the valve and relieve the excessivepressure in the chamber 26. When the excessive pressure is relieved, thecompression spring 66 will again move the pintle downwardly intocooperative relation with the sealing member 70 to reform the seal,being aided by the hemispherical end of the pintle.

Referring now to FIGS. 3, 4 and 5, the check valve seated in core member24 will be described, which retains the fluid pressure conditions inchamber 26 when pump is stopped. As has been pointed out hereinbefore,when the pump 14 is driven by the motor 16, the pressure begins to buildup in the chamber 20, by first closing the normally open valve 21, whichcauses the spool 22 to move to the left in the bore 20a in communicationwith and a part of the chamber 20, until it comes to rest against stopS. The fluid will then flow through slots 22a in the forward end of thespool 22 to impinge against the forward face of the core 24 as shown bythe arrows in FIG. 3. The core 24 is positioned in its bore 241: againsta stop 24b being held mechanically in position by any suitable meanssuch as pin 240, being sealed against leakage by O-rings R as alreadydescribed. The annular chamber 26, is formed in part by a clearance inthe outer surface of the core 24 and by an enlargement in the bore 24aas is best seen in FIGS. 1 and 3, being in communication with thevertical bore 34 in which the relief valve 33 is positioned bypassageway 36, and also in communication with tube 28 by passageway 28aas already described.

The chamber 26 is also in communication with an internal counterbore 26ain the core 24 by means of crossbores 26b and 26c as best seen in FIG.3. The bottom of the bore 26a forms an anchor for a helical spring whichresiliently urges a hexagonal valve member 92 to the left which isslidable in the counterbore 26a to open and close the valve whichcontrols the flow of fluid to and from the chamber 26 as alreadydescribed. The hexagonal conformation of the valve member 92 providesclearances 92a to allow flow of the fluid about the valve member toenter counterbore 26a and then into chamber 26 via bores 26b and 260.The forward or left hand end of the core 24 is provided with a shallowcounter-bore 94, and aperture plate 96 is held in permanently assembledand sealed relation by inturned lip 98.

The fixed aperture plate 96 is provided with a central aperture 96a(FIG. 4), which terminates on the inner side with a circumferential lip96b which is flanked by a depression 960 to provide an annular chamber96d facing the movable valve member 92 with which the plate 96 and thelip 96b cooperate to form the valve. The forward face of the movablevalve member 92 is provided with a forwardly extending head 100 whichextends into the central aperture 96a with minimum clearance. The head100 is preferably tapered to enlarge the clearance as the movable valvemember 92 is retracted during the opening of the valve. Behind the head100, an annular elastomeric sealing member 102 of 90 Durometer hard nessis seated in an annular depression 104 concentric with the head 100 theID. of elastomeric being less than head 100. The outer wall of thedepression terminates in a circumferential wall 106, the forward portionof which is undulating to form a clearance 106a to allow flow of fluidat all times to the chamber 96d, so that the pressure in the chamberwill act on the sealing member 102 to compress it against the head 100and the lip 96!) to form a seal for the valve to hold the fluid pressurein the chamber 26 which is in communication with the chamber 96dCompression on elastomer is limited by the forward portion of hexagonalmember 92 seating on member 96. To assist the fluid pressure to deformand compress the clastomeric member 102, the forward face is cut away toform a lip 102a which is in contact with the lip 96b as is best seen inFIG. 4. The minimum clearance between the head 100 on the movable valvemember 92 and the aperture 96a of the fixed valve plate 96 preventsextrusion of the elastomeric sealing member 102 to give the valvedurability with the power to form an excellent seal.

When the movable valve member 92 is to be retracted to open the valve,the spool 22 upon reversal of pressure application will move to theright (FIGS. 1 and 3) to cause the projection 22b to contact the head100 and provide mechanical force, which may approximate a hammer blow tomove the member 92 to the right to open the valve.

It is to be understood that the above detailed description of thepresent invention is intended to disclose an embodiment thereof to thoseskilled in the art, but that the invention is not to be construed aslimited in its application to the details of construction andarrangement of parts illustrated in the accompanying drawings since theinvention is capable of being practiced and carried out in various wayswithout departing from the spirit of the invention. The language used inthe specification relating to the operation and function of the elementsofthe invention is employed for purposes of description and not oflimitation, and it is not intended to limit the scope of the followingclaims beyond the requirements of the prior art.

What is claimed is:

1. A control valve capable of holding high-pressure for prolongedperiods of time, comprising in combination, an annular sealing member ofelastomeric material of Durometer hardness of at least 80, having acentral annular lip on one side, a movable valve member having acentrally located head and a flange to form a chamber for housing saidsealing member adapted to closely cOnfine the elastomeric materialthereof on at least three sides, a fixed annular sealing surfaceembracing the head cooperating with the central annular lip portion ofthe one unconfined side of said sealing member, resilient means to movethe movable valve member to urge the annular lip of the sealing memberinto contact with the sealing surface, a high-pressure chamber on oneside of said valve adapted to apply pressure to portions of the openunconfined side of the said sealing member outside of the sealingsurface, and a second pressure chamber on the other side of the valve,said high pressure in said high-pressure chamber acting on the centralannular lip and on the open unconfined side of the sealing member inseveral directions to apply sealing pressure on the annular sealingmember.

2. The valve defined in claim 1 further characterized by having themovable valve member provided with the central head extending throughthe annular sealing member to cooperate with an actuatable moving meansto move the valve member and the sealing member from its sealingrelation with the sealing surface.

3. The valve defined in claim 1 further characterized by providingconstricted passageways between the highpressure chamber and the secondpressure chamber for fluid flowing through the valve with minimumdimensions adjacent the sealing surface to prevent extrusion of theelastomeric sealing member therethrough.

4. The valve defined in claim 2 further characterized by having apressure-actuated piston of relatively large area, responsive to a thirdcontrolled pressure, move the movable valve member by contacting thecentral head member to open the valve.

5. The valve defined in claim 3 further characterized by having theconstricted passageways between the high pressure chamber and the secondpressure chamber becoming progressively larger as the movable valvemember moves away from the sealing surface as the valve opens.

References Cited UNITED STATES PATENTS 2,303,392 12/1942 'Slaramulli251-175 X 2,709,065 5/ 1955 Pohndorfi 25 l333 3,900,166 8/1959 Boosman251333 X 3,092,139 6/1963 Rodgers et a1. 251-368 3,198,481 8/1965 Bryant25 l333 X 2,611,390 9/1952 Johnson 137- 494 2,657,533 1 1/ 1953Schanzlin et a1.

2,716,995 9/ 1955 Baugh et al, 1 2,928,243 3/ 1960 Albright -523,009,476 11/1961 Usab 137--516.29 3,301,313 1/1967 Schurink 60-52 XRARHOLD ROSENTHAL, Primary Examiner US. 01. X.R. 6052; 137-516.29;251-175, 333

